1. Technical Field
The present invention relates generally to switching in a packet switched network and, more specifically, to systems and methods for configuring network switching devices.
2. Background Art
At the heart of most networks are switches interconnected via a communications medium. For example, Ethernet is a commonly used local area network scheme in which multiple stations are connected to a single shared serial data path. These stations communicate with a switch located between the shared data path and the stations connected to that path. The switch controls the communication of data packets on the network.
Networks are frequently organized into sub-networks, called subnets. Within a single subnet, packets of information may be directed to their destination devices using a layer 2 Media Access Control (MAC) address that identifies the attached Ethernet devices. When a switch receives a packet with a familiar destination MAC address, it forwards the packet to the output port on the switch that is associated with the MAC address.
Packets transmitted between layer 2 subnets do so using the destination device's IP (Internet Protocol) layer 3 address. More particularly, a transmitting device sending a packet to a destination device outside of the transmitting device's subnet first determines, using the IP layer 3 address, the layer 2 MAC address of a gateway device that bridges the subnets. The gateway device, often called a layer 3 switch, upon receiving the packet, performs address translation, which involves stripping the MAC destination address of the packet and inserting a new MAC destination address that corresponds to the MAC address of the destination device in the destination subnet. The gateway device determines the MAC address to substitute based on the IP address.
A gateway device may be directly connected to a number of subnets, such as three subnets. A table stored in the gateway device may provide a correspondence between each connected subnet and the output ports of the gateway device that connects to the subnet. In operation, when the gateway device receives a packet destined for one of the connected subnets, it looks up the appropriate output ports for the packet in the table.
Managing and updating the table in the gateway device is often done manually by a user located locally to the gateway device. This can be a time consuming and error prone process.
Thus, there is a need in the art to improve table management and updating in a gateway device.